Collapsible portable boat and its method of assembly

ABSTRACT

A light weight, high buoyancy boat is presented which may be collapsed into a compact body and which is made of corrugated thermo-plastic synthetic resin sheets and method of assembly thereof.

United States Patent [191 Tanabe Nov. 13, 1973 COLLAPSIBLE PORTABLE BOAT AND ITS METHOD OF ASSEMBLY [76] Inventor: Daisuke Tanabe, 27, Daikyo cho,

Shinjuku ku, Tokyo, Japan 22 Filed: Sept. 8, 1971 211 Appl.No.: 178,741

[30] Foreign Application Priority Data Feb. 15, 1971 Japan 46/6362 [52] US. Cl. 9/2 R, 9/2 F, 9/6, 46/93, 46/1 L [51] Int. Cl B63b 5/24, 86% 7/04 [58] Field of Search 9/2 C, 2 F, 6;

[56] References Cited UNITED STATES PATENTS 2,028,543 l/l936 Goldberg et al. 9/2 X 3,111,924 11/1963 Ecroyd et al 114/665 R 3,880,429 4/1959 Henry 2,969,551 1/1961 Snider 9/2 C 3,060,464 10/1962 Robison 9/6 Primary Examiner--Milton Buchler Assistant Examiner-Carl A. Rutledge Att0rney-J0hn J. McGlew et al. v

57 ABSTRACT A light weight, high buoyancy boat is presented which may be collapsed into a compact body and which is made of corrugated thermo-plastic synthetic resin sheets and method of assembly'thereof.

10 Claims, 12 Drawing Figures PAIENYEnunvmms 3.771.180

sum 10F 3 INVENTOR DHVSUKE THUR B E avj rfig 772%) ATTORNEY PATENIEU NOV 1 3 1973 SHEET 2 BF 3 FIG. 5

FIG. 7,

FIG, 6

INVENTOR DmsuKE TFWHBE BYWj fl I ATTORNEY PATENTEDMOWBIQB- v 3.771.180 snmacs-s INVENTOR KE *xamsz ORNEY COLLAPSIBLE PORTABLE BOAT AND ITS METHOD OF ASSEMBLY BACKGROUND OF INVENTION As the sports loving population has increased in recent years, there has been a corresponding increase in demands for small sea crafts such as canoes, yachts and boats. These small crafts are usually made of wood, glass fibres, and other hard synthetic resins and while they are sturdy, their sizes and the weights are too great to be carried about easily by hand. Although the samll crafts made of rubber are easy to carry, they are easily broken and require special equipment for blowing the air in and they are still comparatively heavy. Thus, there is a remarkable demand for a light weight, high buoyancy portable boat which may be collapsed easily and is also durable and sturdy in the market so as to serve the purpose of all, young and old, men and women, enjoying boating on the beaches, lakes, rivers, etc.

SUMMARY OF INVENTION The present invention aims to provide a portable boat which may be assembled easily by folding the prefolded line from the corrugated sheet of thermoplastic synthetic resin. A further aim of the invention is a method of assembly of the boat. This boat when provided with reinforcing materials, oar locks, an outboard engine or the like removably may be carried by hand to any place. The present invention further aims at providing a boat with an increased bouyancy because of the provision ofa central stabilizer or float in the direction of the bottom and with an extremely high stability in all the directions of stern, stem or bow, both sides, bottom and top as the water enters between the projecting parts of the float or stabilizer and the bottom of the boat. This high stability is particularly advantageous when used on the water with considerable waves. The present invention will become more apparent from the accompanying drawings and the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4 show the process of assembling the boat according to this invention, and more in particular;

FIG. 1 is a perspective view of a corrugated sheet from which the main body of the boat is assembled;

FIG. 2 is a perspective view showing the boat as assembled;

FIG. 3 is a perspective view of the corrugated sheet for the floats in the folded state;

FIG. 4 is a perspective view of the corrugated sheet for the float before it is folded;

FIG. 5 is a general perspective view of the boat as completely assembled;

FIG. 6 is a cross sectional view taken along the line VIVI in FIG. 5;

FIG. 7 is a partially enlarged view of the part A of FIG. 6; f

FIGS. 8 to 11 are the diagrams showing the process of assembly of a boat in another embodiment of this invention and respectively corresponding to FIGS. 1 to 4; and

FIG. 12 is a cross sectional view taken along the line XII XII in FIG. 9.

DESCRIPTION OF PREFERRED EMBODIMENTS In FIGS. 1 to 7, a plurality of thermo-plastic synthetic resin sheets and are in corrugated form comprising two layers with a space and longitudinal ribs therebetween and made of polypropylene, polystyrene or the like which is easy to inject or to extrude and has considerable resistance against compression, bend-.

. one upon the other will obtain a preferable buoyancy,

but this is not necessarily a requisite. Longitudinal lines or creases in the center and other creases are pressed onto the sheet(s) for folding. The press may be conducted in one operation by predeterminingthe parts where said various creases are to be pressed by means of a jig or the like, and the creases may be manually marked. In FIG. 1, a plane view of a sheet with various creases pressed onto is shown. The center line (11), (21) in the longitudinal direction is first pressed and then the creases (12) to (15), (22) to (25) for folding purposes are pressed. The creases (12) and (22) form the area of a side (40) and a bottom (50) while (13), (23) and (14), (24) form the stem or bow (60) while (13), (23) and (15), (25) form the stern In the drawings, the hatched part are those that are folded on the outside of the boat, the portions indicated by the dotted line indicating the crease for folding. It is however possible to fold the said part into the inside of the boat. In this example of the present invention, two sheets (10), (20) are used for composing the main body by somewhat shifting one in the direction of the ships side X X (FIG. 5). The reason for a plurality of the sheets or blanks is to impart a high buoyancy to the main body or hull, and piling the two with their centers shifted in one direction is to facilitate folding of the side edges (18), (2 8) easily. As shown in FIG. 2, the hatched part is folded toward the outside direction of the boat, the side edges (16) and (26) are heated and fuse welded to form the bow (60) of FIG. 5. In the like manner, the edges (17) and (27) are heated and fuse welded to form the stern. It is possible to obtain a quite sturdy bow and stern if such fixing or fastening means as rivets, bolts and the like are used on the folding sections at the bow and the stern and on the edges of the sides of the boats. (FIG. 7). It is possible to form a bulbous type bow instead of an angular type as shown in the drawings.

Reinforcing materials (41) may be provided on the inner sides of the bow and the stern of the boat thus assembled in order to prevent the sides (40), (40) to bend inwardly along the folding lines (12), (22). The reinforcements (41) may be of the same material as the main body of the boat or of reinforced plastic or oflight weight metal such as aluminum. Said reinforcement (41) is preferably adjacent to the folding line (indicated by dotted line in FIG. 5) for carrying the same so as to contribute toward the strength of the boat. In the embodiment shown in the drawings, the reinforcements (41) were provided at two parts. The two longitudinal sides (18) (28) of the sheet are fixed or fastened by bolts or the like after heating and fuse welding the parts that have been folded inwardly or outwardly so as to form the edge of the boat. Oar locks (42) of rubber may be attached on two edges thus formed, but they are not necessary when the craft is used as a canoe. An outboard engine may be arbitrarily provided either at the bow (60) or at the stern (70). A float or central stabilizer (30) made of the same material as the main body of the boat may be assembled in such a way that the corrugation in the longitudinal direction thereof is in a perpendicular relation to that of the sheets (20) for the main body or hull so as to achieve an almost perfect leakage prevention into the spaces within the sheets or blanks. The manner in which the sheets are arranged is shown in FIG. 5 in a partial fragment al view of the surface of the sheet.

The sheet or blank (30) for the float or central stabilizer is pressed with the creases for folding the boat (FIG. 4) in the like mannerfor the sheet or blank of the main body. The sheet or blank is folded as shown in FIG. 3, attached to the side of the body or hull, heated, fuse welded and riveted or fastened to secure the contacts of the outside of the sides (40), the bottom (50) and the contacting surface of the said sheet or blank (30). In this embodiment, the edges (31) of the sheet (30) are intercepted as the edges (18), (28) of the side of the boat are folded and riveted or fastened by the rivet or fastener (43) so as to form one body (FIG. 7), and the contacting planes (32), (33) with the sides (40) and the bottom (50) are adhered tightly by means of adhesive agent. In the manner as described heretofore and as shown in FIGS. 5 and 6, the float or central stabilizer provided with projections (80), (80) projecting downwardly from the bottom is attached to the main body or hull of the boat. The shape of the float or stabilizer is not limited to the one shownin FIGS. 3, 5 and 6 and any shapes so long as they project downwardly from the bottom are acceptable.

It is quite easy to fold the boat after its use. The reinforcing materials (41) are removed first and the parts forming the bow and the stern areopened up in the outward directions. The sides (40), (40) are automatically pulled toward the inside 'by the creases (12), (22). The bottom (50) is then folded along the creases (11), (21) so that the said folding creases will move upwardly while the sides move downwardly and the boat is folded in a symmetrical folding position in respect of the center line Y Y in FIG. 5. The float is at the same time folded and piled together toward the inside at the points indicated by the dotted line in FIG. 5. The completely reverse order may be employed when the boat is being prepared for use on the water.

(EXAMPLE TEST) Three pieces of sheets having the properties of Table l and made of 3.85 mm thick polypropylene copolymer sheet (marketed under the trade name DANPLA-ACE by Tokyo Kogyo Co. (Tokyo, Japan)) are used in assembling a boat having the dimensions of 140 cm length, 80 cm width, 30 cm height from the bottom to the side, 45 cm high float on which creases as shown in FIGS. 1 and 4 have been pressed. The boat thus obtained was light weight, stable and had a high buoyancy as disclosed hereinbelow.

TABLE 1 Compression Bending Tensile Elonga- Impact strength force force tion value 4 kg kg/cm kg kg/cm kg kg/cm k kg/cm' 6.] 4.0 L0 31.0 8.1 42.1 490 66.l

Buoyancy 300 kg Weight 2.0 kg Weight of accessories 5.0 kg

The result revealed that a two seater boat according to this invention has a buoyancy equivalent of a four seater and that its weight is extremely light compared to the weight of a rubber boat which is approximately kg when seating one person and is therefore extremely suitable for carrying by hand. The mechanical properties of the sheet as shown in Table l have been confirmed to be such that the boat made of the same is quite safe.

Another embodiment of the present invention is now explained, references being made to FIGS. 8 to 12. The method of assembly and the structure thereof being approximately the same as those of the first embodiment of the present invention, the description thereof is being eliminated. The reference numerals used in the drawings are in three digits and those identifying the identical or corresponding parts in the two embodiments have the identical numbers in the last two digits. The embodiment in FIGS. 8 to 12 is characterized in that only one sheet of material is used and that the bow is bulbous and that the shape of the float is unique. As shown in FIG. 9, a crease (114) marking the hatched part to be folded inside is pressed on the edge part (116) of the corrugated sheet of thermo-plastic synthetic resin. The hatched part is folded either inwardly or outwardly and the edges of the folded parts are brought together to form a bulbous bow as shown in FIG. 9. The stern may be formed in the like manner when the craft is to be used as a canoe. The stem of the embodiment as shown in FIG. 9 shows that the edge part (117) is folded inwardly, which is the reverse of the first embodiment. The reinforcing materials (141) are attached after the boat is thus assembled which is made of the same material as the said sheet and formed in a hollow square post. Into the hollow part thereof is inserted a piece bent in a shape of V so as to increase the resistance against the bending force. The reinforcement made of the same thermo-plastic resin is more preferable from the economical point of view and from the buoyancy. When attaching the said reinforcement (141), a plate (144) cut out of the same material should preferably be placed within the boat in order to still reinforce the bottom of the boat. A float or stabilizer folded in the manner as shown in FIG. 10 and made from the same material as the main body of the boat is attached to the boat thus assembled. The projecting parts (180) project in the oblique direction downwardly in the right and left directions in respect of the boat bottom so as to achieve higher stability against the'rolling in respect of the direction X X compared to.the embodiment shown in FIG. 6. The method of attaching the float (130) to the main body is substantially the same as in the first embodiment.

The present invention as hereinbefore described provides a boat which may be easily assembled by pressing creases for folding by a simple pressing process or manually on the thermo-plastic synthetic resin corrugated sheet cut out in an arbitrary size and by adhering the edges thereof by heatingand welding and/or rivetting. Moreover, a float or stabilizer for improving buoyancy, strength and stability may easily be attached thereto. When the assembly of a light weight boat having high buoyancy is so easily facilitated by a mere simple assembly operation and if all the accessories such as reinforcing materials, oar locks and outboard engines are removably attached, then it becomes possible to carry such boat to any place where there is water. Thus, such a boat becomes most useful not only for leisure and sport purposes but also for emergencies such as floods and other disasters. As the coloring of the boat is quite easy, it offers a beautiful boat. The float provided projectingly extending from the bottom not only increases buoyancy, but contributes greatly toward the stability in the directions of X X, Y Y, and Z Z as shown in FIG. 5 as the water comes into the spaces between the float and the bottom. (See FIGS. 6, (34) (34), 12 (134) (135). This advantage will prove extremely valuable when the boat is used on the wavy seas. The boat shown in the drawings has a float or stabilizer of which the length is shorter than the length of the main body of the boat, but it is quite easy to provide a float of identical length with the boat.

I claim:

1. Assembly of blanks for forming a collapsible structure, such as a boat, comprising a. at least one body forming blank which comprises a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer; a first crease impressed in the center of said body forming blank running longitudinally from one end to the other end of said blank in the same direction as said rib members; said blank being creased around its periphery so as to form a center portion and flaps adapted to be folded upward to form the sides of said structure; and

b. at least one stabilizer blank which comprises a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer; two central creases running longitudinally from one end to the other end of the stabilizer blank defining a central flat stabilizer area; two bottom surfaces adajcent each of said central creases, each of said bottom surfaces having at least one crease running longitudinally from one end to the other end of said bottom surface; and two outermost side portions adjacent each of said bottom surfaces and adapted to be fastened to the flaps of the body forming blank when folded upward forming the sides of said collapsible structure.

2. Assembly of blanks for forming a collapsible structure, according to claim 1, wherein said body forming blank is substantially rectangular and includes a. second and third creases running parallel to said first crease and spaced symmetrically between said first crease and the sides of the blank substantially parallel to said first crease;

b. fourth and fifth creases running substantially at right angles to said first crease and spaced from the ends of said body forming blank substantially the same distance as the second and third creases are spaced from the edges of said body forming blank; and

0. four diagonal creases running from each corner of said body forming blank to the intersections of each of the second and third creases, with each of the fourth and fifth creases respectively.

3. Assembly of blanks for forming a collapsible structure, according to claim 1, wherein each of said bottom surfaces includes a single crease running longitudinally from one end to the other end of said bottom surface.

4. Assembly of blanks for forming a collapsible structure, according to claim 1, wherein each of said bottom surface includes two creases running longitudinally from one end to the other end of said bottom surface.

5. A collapsible boat, which comprises a. a hull comprising a central body area formed from at least one body forming blank having flaps which are foldable upwardly along each end and side to form sides,-stern and bow areas of said hull, said body forming blank comprising a flat top layer, a flat bottom layer, and a-plurality of rib members connecting said top layer to said bottom layer; and

b. a central stabilizer'connected to the bottom of said hull and extending downwardly forming two bottom surfaces having each an outermost side portion extending upwardly and adapted to be fastened to the flaps forming each side of said hull, said central stabilizer comprising a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer.

6. A collapsible boat, according to claim 5, wherein said central stabilizer comprises a substantially rectangular flat area, a substantially vertical connecting panel on each side of said flat area adapted to be oriented at an angle to the flat area, a horizontal stabilizing panel connected along the complete length of each of said connecting panels, an outer side panel secured to each of said horizontal stabilizing panel in substantially vertical orientation and adapted to be secured to the sides of the hull.

7. A collapsible boat, according to claim 5, wherein said central stabilizer comprises a substantially rectangular flat area, a connecting panel on each side of said flat area adapted to be oriented at an angle to the flat area, an outer side panel secured along the complete length of each said connecting panel forming a substantially V-shaped member therewith and adapted to be secured to the sides of the hull.

8. Method of making a collapsible boat, which comprises a. forming at least one body forming blank having a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer, impressing a first crease in the center of said body forming blank running longitudinally from one end to the other end of said blank in the same direction as said rib members, creasing said blank around its periphery so as to form a center portion and flaps adapted to be folded upward to form the sides of the boat;

b. forming a stabilizer blank having a flat top layer,

a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer, impressing two central creases running longitudinally from one end to the other of the stabilizer blank, defining a central flat stabilizer area, impressing at least two creases on either side of said central flat stabilizer area defining two bottom surfaces adjacent said central flat stabilizer area and two outermost side portions adjacent said bottom surfaces and adapted to be fastened to the flaps of the body forming blank when folded upward to form the sides of the boat;

0. folding the flaps of the body forming blank upwardly to form the sides, bow and stem of the boat and securing said flaps by fastening means, and

substantially vertical orientation and adapted to be secured to the sides of the hull.

10. Method of making a collapsible boat, according to claim 8, said central stabilizer being formed of a substantially rectangular flat area, a connecting panel on each side of said flat area adapted to be oriented at an angle to the flat area, an outer side panel secured along the complete length of each said connecting panel forming a substantially V-shaped member therewith and adapted to be secured to the sides of the hull. 

2. Assembly of blanks for forming a collapsible structure, according to claim 1, wherein said body forming blank is substantially rectangular and includes a. second and third creases running parallel to said first crease and spaced symmetrically between said first crease and the sides of the blank substantially parallel to said first crease; b. fourth and fifth creases running substantially at right angles to said first crease and spaced from the ends of said body forming blank substantially the same distance as the second and third creases are spaced from the edges of said body forming blank; and c. four diagonal creases running from each corner of said body forming blank to the intersections of each of the second and third creases, with each of the fourth and fifth creases respectively.
 3. Assembly of blanks for forming a collapsible structure, according to claim 1, wherein each of said bottom surfaces includes a single crease running longitudinally from one end to the other end of said bottom surface.
 4. Assembly of blanks for forming a collapsible structure, according to claim 1, wherein each of said bottom surface includes two creases running longitudinally from one end to the other end of said bottom surface.
 5. A collapsible boat, which comprises a. a hull comprising a central body area formed from at least one body forming blank having flaps which are foldable upwardly along each end and side to form sides, stern and bow areas of said hull, said body forming blank comprising a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer; and b. a central stabilizer connected to the bottom of said hull and extending downwardly forming two bottom surfaces having each an outermost side portion extending upwardly and adapted to be fastened to the flaps forming each side of said hull, said central stabilizer comprising a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer.
 6. A collapsible boat, according to claim 5, wherein said central stabilizer comprises a substantially rectangular flat area, a substantially vertical connecting panel on each side of said flat area adapted to be oriented at an angle to the flat area, a horizontal stabilizing panel connected along the complete length of each of said connecting panels, an outer side panel secured to each of said horizontal stabilizing panel in substantially vertical orientation and adapted to be secured to the sides of the hull.
 7. A collapsible boat, according to claim 5, wherein said central stabilizer comprises a substantially rectangular flat area, a connecting panel on each side of said flat area adapted to be oriented at an angle to the flat area, an outer side panel secured along the complete length of each said connecting panel forming a substantially V-shaped member therewith and adapted to be secured to the sides of the hull.
 8. Method of making a collapsible boat, which comprises a. forming at least one body forming blank having a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said botTom layer, impressing a first crease in the center of said body forming blank running longitudinally from one end to the other end of said blank in the same direction as said rib members, creasing said blank around its periphery so as to form a center portion and flaps adapted to be folded upward to form the sides of the boat; b. forming a stabilizer blank having a flat top layer, a flat bottom layer, and a plurality of rib members connecting said top layer to said bottom layer, impressing two central creases running longitudinally from one end to the other of the stabilizer blank, defining a central flat stabilizer area, impressing at least two creases on either side of said central flat stabilizer area defining two bottom surfaces adjacent said central flat stabilizer area and two outermost side portions adjacent said bottom surfaces and adapted to be fastened to the flaps of the body forming blank when folded upward to form the sides of the boat; c. folding the flaps of the body forming blank upwardly to form the sides, bow and stern of the boat and securing said flaps by fastening means, and d. fastening the outermost side portions of the central stabilizer to the sides of the boat by fastening means.
 9. Method of making a collapsible boat, according to claim 8, said central stabilizer being formed of a substantially rectangular flat area, a substantially vertical connecting panel on each side of said flat area adapted to be oriented at an angle to the flat area, a horizontal stabilizing panel connected along the complete length of each of said connecting panels, an outer side panel secured to each of said horizontal stabilizing panel in substantially vertical orientation and adapted to be secured to the sides of the hull.
 10. Method of making a collapsible boat, according to claim 8, said central stabilizer being formed of a substantially rectangular flat area, a connecting panel on each side of said flat area adapted to be oriented at an angle to the flat area, an outer side panel secured along the complete length of each said connecting panel forming a substantially V-shaped member therewith and adapted to be secured to the sides of the hull. 